1. Field of the Invention
The present invention relates to a density detection device and an image forming apparatus including the same.
2. Background Art
A density detection device is a device for detecting density of solute or dispersoid in liquid. A conventional density device has been configured to irradiate a liquid layer in a narrow gap formed in a liquid container with a light and to detect the density of the liquid based on a decay ratio of the light transmitting through the liquid layer.
According to the conventional density detection device, however, flow of the liquid around the narrow gap may affect formation of the liquid layer. For example, pressure of the liquid around the narrow slit may prevent the liquid layer from being formed in the desired thickness. Additionally, every time the liquid layer is formed, its thickness may vary. In such a case, it is difficult to detect accurately the liquid density.
Furthermore, according to the conventional density detection device, it is necessary to move accurately a moving unit to a predetermined position for enhancing accuracy of the density detection. However, thickness of the liquid layer will be unstable when the moving unit tilts against the wall of the liquid container or when the tilt angle of the moving unit against the wall varies every time the density detection is executed. Consequently, accuracy of the density detection will be lowered.
Also, according to the conventional density detection device, the top of the liquid container is opened. Liquid in the liquid container may leak out of the liquid container when the moving unit is moved.